Polyacrylonitrile-grafted reduced graphene oxide hybrid: An all-round and efficient hole-extraction material for organic and inorganic-organic hybrid photovoltaics

In this research, we demonstrate that aliphatic polyacrylonitrile-grafted reduced graphene oxide (PRGO) hybrid can function efficiently as an all-round hole-extraction layer (HEL) in organic and organic-inorganic hybrid perovskite photovoltaic devices (OPVs and PePVs). The hybrid-structure PRGO was developed by facile and scalable in-situ radiation-induced reduction and graft polymerization with polymerizable styryl-functionalized graphene oxide and acrylonitrile. The newly developed PRGO exhibits long-term dispersion stability of six months even up to the high concentration of 10 mg/ml. It also shows a full-cover uniform thin-film morphology, good electrical conductivity (0.87 S/cm), high work function (4.87 eV), and excellent weather stability. Moreover, the incorporation of PRGO (as a HEL) into the OPVs and PePVs results in greater efficiency than chemically-converted graphene nanoflakes references, and device durability superior to poly(ethylenedioxythiophene):poly(styrene sulfonate)-based ones with comparable power conversion efficiencies. Noticeably, our finding demonstrates that the hybrid-structure PRGO provides an all-round and efficient hole-extraction material for use in various conjugated-polymer and perovskite-based PV systems.